Cosmetic materials are known which are blended with sterol compounds such as cholesterol and phytosterol in order to impart moistness to the skin or hair.
However, these sterol compounds are high melting point compounds as can be seen from the fact that the melting point of cholesterol is 149° C., and to use them as cosmetic material compositions, they must first be dissolved with heating or liquefied with a solvent before blending. If they are dissolved with heating, there is a problem that they cannot be blended with other components having poor heat stability. Also, when liquefying and blending, as they have a low solubility in solvents, only low concentration solutions could be prepared and only limited cosmetic material compositions could be obtained. Further, if crystallinity is high, crystals of sterol compounds separate and deposit during storage, so it is difficult to maintain storage stability.
It is known that crystallinity can be reduced by making the sterol compound react with a higher fatty acid to obtain a liquefied ester compound. However, when they contained such an ester compound, the cosmetic materials became sticky when applied to the skin, and it was difficult to obtain cosmetic materials having excellent organic functional characteristics.
To exploit the moistness of sterol compounds, it is desirable to make them into emulsions such as oil-in-water or water-in-oil, but as the sterol compound itself and the above-mentioned higher fatty acid ester had low hydrophilic properties, an activator had to be used to make the emulsion composition, and a decline of organic functionality due to this activator could not be avoided.
It is also known that adding ethylene oxide to a sterol compound reduces crystallinity, imparts hydrophilic properties and leads to an emulsion-type compound. However, the stickiness on the skin could not be eliminated.
To improve organic functionality, a sterol-modified silicone compound has also been developed (Japanese Patent Application Public Disclosure No. Hei 4-145097, Koho), but a satisfactory cosmetic material could still not be obtained.
The Inventors carried out intensive studies in order to solve the above-mentioned problems. They then discovered a sterol-modified silicone compound having low crystallinity, no stickiness on the skin, excellent organic functionality and hydrophilic properties.
It is therefore a first object of this invention to provide a sterol-modified silicone compound suitable for an emulsion composition having a low melting point, and hydrophilic properties.
It is a second object of this invention to provide a cosmetic material having excellent stability and moistness.